Method of producing a sandwich panel core of mineral wool fibres

Abstract

A method of producing a sandwich panel core of mineral wool fibers from a cured mineral fiber product includes the steps of providing a cured mineral fiber product with a dual density having a top layer with mineral fibers with a first density and a base layer having mineral fibers with a second density, the second density is at least two times lower than said first density. The top layer and the base layer have different fiber orientations. Further steps including cutting the mineral fiber product into a plurality of lamellae, rotating the lamellae 90 degrees, and re-joining the lamellae so that the top layers with the first density are vertically oriented.

The invention claimed is: 
     
       1. A method of producing a sandwich panel core of mineral wool fibres from a cured mineral fibre product, said method comprising the steps of:
 providing a cured mineral fibre product with a dual density comprising a top layer comprising mineral fibres with a first density and a base layer comprising mineral fibres with a second density, said second density being at least two times lower than said first density, and said top layer and said base layer having different fibre orientations; 
 cutting said mineral fibre product into a plurality of lamellae; 
 rotating each of said lamellae 90 degrees; and 
 re-joining said lamellae so that said top layers with said first density are vertically oriented. 
 
     
     
       2. The method according to  claim 1 , wherein the step of re-joining comprises adhering the cut and rotated lamellae to each other by applying an adhesive. 
     
     
       3. The method according to  claim 1 , wherein said cured mineral fibre product is formed by the steps of:
 providing a top layer web comprising uncured mineral wool; 
 providing a base layer web comprising cured mineral wool; 
 joining said uncured top layer web and said cured base layer web to form an assembled laminate; 
 curing said top layer web in a curing oven by transporting the assembled laminate into a curing oven comprising an upper conveyor and a lower conveyor for curing said assembled laminate, said assembled laminate being positioned between said upper and lower conveyors; 
 wherein said uncured top layer web is compressed by at least 50% upon entry into said curing oven. 
 
     
     
       4. The method according to  claim 3 , wherein the fibre orientation of said top layer is substantially horizontal before the step of cutting. 
     
     
       5. The method according to  claim 3 , wherein the fibre orientation of said base layer is substantially vertical before the step of cutting. 
     
     
       6. The method according to  claim 3 , wherein said top layer after compression is provided with a first density of two to three times the second density of the base layer. 
     
     
       7. The method according to  claim 1 , wherein said first density is 150-300 kg/m3. 
     
     
       8. The method according to  claim 1 , wherein the second density is 50-100 kg/m3. 
     
     
       9. A mineral wool fibre panel core made by performing a method according to  claim 1 , wherein the panel comprises first and second elongate elements which are parallel to each other, and wherein the first elongate elements have a first density and with a fibre orientation parallel to the top and bottom surfaces of the panel, and the second elongate elements have a second density and with a fibre orientation substantially orthogonal to the top and bottom surfaces. 
     
     
       10. A panel according to  claim 9 , wherein a width of first areas of the base layer in each of said lamellae is 80-90 mm and a width of second areas of the top layer in each of said lamellae is 15-20. 
     
     
       11. A sandwich panel comprising a sandwich panel core according to  claim 9 , and further comprising a metal facing on the top and bottom surfaces of the sandwich panel core. 
     
     
       12. A panel according to  claim 9 , wherein a width of first areas of the base layer in each of said lamellae is 85 mm and a width of second areas of the top layer in each of said lamellae is 17 mm. 
     
     
       13. The method according to  claim 1 , wherein said first density is approximately 230-250 kg/m3. 
     
     
       14. The method according to  claim 1 , wherein said first density is approximately 65-70 kg/m3.